The expression of the Epstein-Barr virus nuclear antigen (EBNA-I) in oral hairy leukoplakia.
OBJECTIVE
Oral hairy leukoplakia (OHL) is characterised by the presence of a replicative Epstein-Barr virus (EBV) in the superficial layers of the epithelium. There is some doubt, however, whether this reflects activation of a latent infection of the basal epithelial cells. EBV latency is associated with the expression of the viral gene product EBNA-I and the aim of this study was to investigate EBNA-I expression in OHL.


METHODS
22 biopsies of clinically suspicious OHL and three cases of normal mucosa were available as fresh frozen or paraffin embedded material. EBNA-I was detected immunocytochemically using a rat monoclonal antibody (IH4-I) following microwave irradiation. Lytic EBV infection was confirmed by the identification of the BZLF-I protein.


RESULTS
16 of the 22 cases displayed focal replicative EBV meeting the criteria for OHL, and in 13 of these, EBNA-I expression was restricted to the nuclei of epithelial cells in the upper layers of the epithelium. EBNA-I expression was absent from the basal cells in all cases and in the nine BZLF-I negative mucosal biopsies.


CONCLUSIONS
These findings suggest that lytic EBV infection in OHL is not the result of activation of a latent infection of basal cells and suggests a role for EBNA-I, not only in latent EBV infection, but also in virus replication.
Cruchley
A T
AT
Department of Oral Pathology, St Bartholomew's, London, UK.
Murray
P G
PG
Niedobitek
G
G
Reynolds
G M
GM
Williams
D M
DM
Young
L S
LS
D017088:AIDS-Related Opportunistic Infections / Q000276:immunology / Q000821:virology*; D000818:Animals; D000911:Antibodies, Monoclonal; D004847:Epithelial Cells / Q000276:immunology / Q000821:virology; D019309:Epstein-Barr Virus Nuclear Antigens / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D006566:Herpesviridae Infections / Q000276:immunology* / Q000821:virology; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology*; D006801:Humans; D017733:Leukoplakia, Hairy / Q000276:immunology* / Q000821:virology*; D009061:Mouth Mucosa / Q000276:immunology / Q000473:pathology / Q000821:virology; D051381:Rats; D017735:Virus Latency; D014779:Virus Replication / Q000502:physiology
D000911:Antibodies, Monoclonal; D019309:Epstein-Barr Virus Nuclear Antigens